Unless you're used to knuckle pushups you'd naturally feel better on your middle, ring and pinky knuckles, because there's more knuckles to spread your weight across. If you're actually conditioned you shouldn't have much of a problem doing them on the correct knuckles (the index [or 'pointer'] and middle).

A "boxer's fracture" is a fracture of the ring-finger knuckle, is it not? The bottom two are not designed to take the kind of force that the top two can. That's why anyone who wants to make money punching uses the index and middle knuckles.

Lord Krishna said: I am terrible time the destroyer of all beings in all worlds, engaged to destroy all beings in this world; Of those heroic soldiers presently situated in the opposing army, even without you none will be spared.Bhagavad Gita 11:32

Many of the karate styles hit with the first two knuckles, other styles use the last three knuckles (index, ring and pinky). What's been your experience with each?

When doing push-ups on my fists, I find it more comfortable using the three (IRP).

when doing pushups in class we switch it up, I use both index/middle for some and the other three as well. To me the index/middle knuckle pushups feel better.

I think this has question already been discussed numerous time here. As I already mentioned in an earlier thread which I dont have time to look up.. as a student in x-ray school (now soon to graduate) one of the most common fractures of all is a boxers fracture to the ring &/or pinky knuckle. Never have seen a boxers fracture to the index or middle as of yet and haven't heard one mentioned from the experienced x-ray "vets". What does all this limited experience mean to me? I think it is more natural to hit with all knuckles, but without proper form the last two (ring/pinky) are far more vunerable than the index/middle knuckles, which is why its not common for a drunken punch fest to end in a broken index/middle, and it is very common for a drunken punch fest to end in a broken ring/pinky knuckle fracture= fracture of the 4th/5th metacarpal bones.

In conclusion, crazys/pissed teenagers/ & drunks all break the ring/pinky knuckles not the index/ring knuckles. So I use the index/middle because they are not the ones commonly broken in punching related injurys.

remember. Your fingers have no muscles, so your push ups are from your forearms up. if you have strong forearms etc.., then its easy to do push ups on any knuckle.

The problem with strikes with your knuckles is that they are not all equal in mass.. the bones in your index and middle are larger, while the bones in your ring and pinky are smaller.. This is why it's generally better to condition the ring and pinky, or stick to striking with your index and middle.

I learned the hard way with this.. hit a guy square with the ring and pinky.. My left pinky knuckle is flattened now. The good thing is that I still have mobility in the finger due to the fact that I only need mere forearm strength to retain movement.

My opinion.. learn to strike effectively, for now, with your first two.. while conditioning the last two.

If you know how to do a proper knife hand, then your thumb is braced against the integrity of the rest of your hand.

There are three nerves that run to your hand.. the median, ulnar, and radial.. They all have about equal function.. so.. regardless.. you're gonna have to condition your hands and strengthen them to minimize pain.

remember. Your fingers have no muscles, so your push ups are from your forearms up. if you have strong forearms etc.., then its easy to do push ups on any knuckle.

The problem with strikes with your knuckles is that they are not all equal in mass.. the bones in your index and middle are larger, while the bones in your ring and pinky are smaller.. This is why it's generally better to condition the ring and pinky, or stick to striking with your index and middle.

I learned the hard way with this.. hit a guy square with the ring and pinky.. My left pinky knuckle is flattened now. The good thing is that I still have mobility in the finger due to the fact that I only need mere forearm strength to retain movement.

My opinion.. learn to strike effectively, for now, with your first two.. while conditioning the last two.

If you know how to do a proper knife hand, then your thumb is braced against the integrity of the rest of your hand.

There are three nerves that run to your hand.. the median, ulnar, and radial.. They all have about equal function.. so.. regardless.. you're gonna have to condition your hands and strengthen them to minimize pain.

EDIT:: and that means strengthening your forearm up, and building the skink around your knuckles.. you get a good example of this when you look at Kimbo Slice's knuckles..